Technical Abstract:
Carbon dioxide (CO2), the principle gas associated with global warming, is also one of four resources needed for plants to complete their life cycle (i.e. water, light, nutrients, CO2). The ongoing increase in its concentration may allow rice breeders to begin selecting for optimal varieties among current rice lines. Cultivar x CO2 interaction has, in fact, been observed for rice, indicating that breeders could begin selecting for CO2 sensitive cultivars as a means to enhance yields for the 21st century. However, desirable phenotypic or genotypic characteristics associated with CO2 responsiveness in rice or other cereals have not been entirely elucidated. In addition, other environmental variables need to be considered in tandem. For example, initial studies suggest that any improvement of rice yield with increasing CO2 will be dependent on nitrogen. Other abiotic parameters likely to change in parallel with carbon dioxide, particularly temperature, could also act in an antagonistic fashion with respect to rice yield. Given these observations, it seems reasonable to suggest that a more thorough evaluation of rice germplasm to global climate change is warranted, even necessitated. Unfortunately, at present, we are unaware of any such systematic evaluation in regard to CO2/climate at the government, university or corporate level for any country. Yet, such an evaluation could utilize to great effect our knowledge of the rice genome/genetics as a means to adapt, or even improve, rice yields in the face of climatic uncertainty.